The invention relates generally to circuit board interfacing and, more particularly, to interfacing a stacked arrangement of circuit boards to a common backplane.
As more functionality is added to electrical circuits and as electrical components become more miniaturized, the demand for circuit board interfaces with multiple interface connections has increased. Additional challenges are produced by the increasing speeds and density of signals transmitted across circuit board interfaces. It would be desirable to address these issues without adding bulk or complexity to the systems.
One approach to addressing these issues is in the use of stacked or tiered daughter boards that are interfaced with a common backplane or mid plane board. Heretofore, tiered circuit boards were arranged using standoffs to mechanically link the daughter boards together. In some applications, such as with low speed card edge connectors, for example, tolerances are such that standoffs can be used with satisfactory results. While standoffs join the circuit boards together, they are not closely coupled to the interface connectors. In the case of high speed, high density connections, the resulting lack of precision in positioning the circuit boards with standoffs causes problems.
As an alternative to standoffs, high speed, high density interfaces often position all of the interface connectors on one board and use guide pins for aligning the boards being mated. Standoffs may also be used, but only to separate the stacked circuit boards.
With the growing demand for interface connectors on multiple stacked boards that interface to a common backplane, the problems with tolerance and precision still exist.